1) What is Meta data and Why Meta data is important and a) What are different types of Meta data in Data Warehousing b) Provide a brief description for each type of Meta data in data warehousing c) How Meta data in data warehousing is differ from Meta data in databases.

Metadata is the data that describes other data, serving as an informative label.

In computing it can be seen as a structured information about a file (date created, creator, software used to create, last modified, file format, file fingerprint, etc)

Explanation:

Why is Metadata Important?

• For to identify unique records

• Aggregating content based on common attributes or types

• Search indexes metadata

• Collate filtered views

• Browse

• Security and permissions

• Workflow and Document lifecycle

Data warehousing.

Warehousing - The act of storing goods in a warehouse.

Metadata can be seen as summarized data that leads us to detailed data. It is a road-map, defines the warehouse objects, acts as a directory.

A data warehouse, is a medium with created metadata for the data names and definitions of a given data warehouse. Data extractions from this warehouse is often time-stamped by other metadata and also show its source.

The description for each type of Meta data in the data warehouse can be seen categorized into Business, Technical and Operational Metadata.

• Business Metadata − this category embodies the ownership information, business definition, and changing policies.

Technical Metadata − It embodies database system names, key attributes and indices (structural information), data types and allowed values, table and column names and sizes.

Operational Metadata − It embodies both the currency of data and data lineage. Currency of data shows whether the data is archived, active, or purged. Lineage of data shows the history of data migrated and transformation applied on it.

Meta data is a set of data that describes and gives information about other data.

Explanation:

A)(i) Meta data is a set of data that describes and gives information about other data.

(ii) Metadata is important because, it acts as a directory which helps the decision support system to locate the contents of the data warehouse. It is also important in loading functions and is a good query, extraction and cleaning tool.

B) - Business Metadata: This has the data ownership information, business definition, and changing policies.

- Technical Metadata: This includes database system names, table and column names and sizes, data types and allowed values. Technical metadata also includes structural information such as primary and foreign key attributes and indices.

- Operational Metadata − This includes currency of data and data lineage. Currency of data means whether the data is active, archived, or purged. Lineage of data means the history of data migrated and transformation applied on it.

C) In a data warehouse, metadata is used for the data names and definitions of a given data warehouse. Along with this metadata, additional metadata is also created for time-stamping any extracted data, the source of extracted data. Whereas, in databases, metadata is created to store data in a structured manner that is organized in tables and columns and extended with primary and unique constraints on the data, foreign keys, check constraints or data types.

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